An update regarding where Epic stands on the issue:
On the Paper2D side
“Support for importing vector formats” was added to the task wishlist in May 2014.
On the UMG Side
For Vector Graphics using Tessellation: “It’s not super high on the list of things we want to tackle. It’s something we may look at in the far future.”
For Vector Graphics using CPU Rasterisation: No plans themselves for offline rendering, but “will gladly accept pull requests to put it in the engine”.
[Insert YouTube Link to “Support Stream - Unreal Motion Graphics (UMG) UI - Oct. 21, 2014” at 40:00 when available]